Infrared and directional insulation?

[Carlobrand]

I'm exploring some ideas around High Guard 2's hit system.

Periodically, the forum breaks into a debate about stealth or lack of same in space - the basic problem being that, 1) Traveller ships put out a lot of power, therefore heat, and 2) against the backdrop of space, objects warmer than the typical asteroid tend to stand out like a sore thumb.

One thing that was settled on - I think - is that while there are some pretty marvelous modern insulators, one can't insulate a ship to stealth levels for very long without basically cooking the occupants. In the context of Traveller ships and their impressive power plants, "very long" is defined as something way, way under the length of the typical space combat turn. Ergo, stealth is not really an option, MegaTraveller's sensor rules notwithstanding.

Then came the idea of directional insulation - applying insulation to one or more facings of your ship while alowing the other facings to radiate away your heat. Dump your heat, just not where he can see it. That has some interesting applications if you want to coast in to some world behind an insulating "umbrella" - except of course that an umbrella big enough to do the job for the typical ship is also going to create a puzzling "hole" where stars should be shining through, giving itself away. Trying to hide that way while vigorously maneuvering in the typical Traveller "most of my thrust comes from the drive in back" ship is hard to conceive and harder to plan a game around, and it's very likely you can't insulate well enough to be completely invisible in infrared, so write that one off.

However, there may be some other uses to the idea besides stealth. Consider a ship that's directionally insulated. Consider it maneuvering, turning, spinning on its axis. Consider its appearance on infrared detection: a heat source of wildly variable magnitude.

Laser doesn't care how hot you are - it just needs to be pointed and shot. Particle beams, probably the same. Missiles, if they're tracking on infrared, might experience some confusion, but keep moving toward it until you hit it is a safe missile rule; however, if the target emits countermeasures that likewise blink variably or intermittently flash an infrared laser at the missile to appear to be "hotter" than they really are, then there may be some potential for a missile to be fooled and caused to waste fuel chasing ghosts.

As for mesons - ranging an object by infrared might be very tricky under such circumstances, and the meson is something that needs very precise ranging information. MegaTrav's neutrino detectors and densitometers offer alternate methods to get that information, and its possible parallax could give you an accurate range despite the flickering.

Now, of course, none of this affects active sensors, but we're assuming the firing ship prefers not to flash his active sensors and become an easy target himself.

So the question: do you think some form of directional insulation could be used, not as stealth, but as a means to confuse pinpoint sensors and make the ship harder to hit? Could it account for the relative inaccuracy of weapons seen in High Guard 2? Would it affect missiles? Would it affect mesons? Would it - contrary to my belief - affect beam weapons? Or is it just some foolish speculation by a guy with an incomplete understanding of the physics involved?

 

[CosmicGamer]

So the question: do you think some form of directional insulation could be used, not as stealth, but as a means to confuse pinpoint sensors and make the ship harder to hit?

IYTU anything is possible and the only people that have to answer that are the players and the GM.

Or is it just some foolish speculation by a guy with an incomplete understanding of the physics involved?

Who cares what we think. See above. Or is this just a mind exorcise? (the spelling is as intended)

Would it affect missiles? Would it affect mesons? Would it - contrary to my belief - affect beam weapons?

I've not looked at high guard in depth for a long time and I am no expert in physics but off the top of my head there is the concept that weapons need to lock onto the target. The more sensors that can lock on the more data available for targeting programs and such to calculate and predict an enemy's location.

 

[BytePro]

Detection outside combat range is not a given just because a ship is radiating. Such depends on resolving power and factors of resolution and integration times - if it was just about heat we would all be able to see every galaxy with our naked eyes. LBB CT M-Drives explicitly provide acceleration, btw, not thrust - so a lot depends on individual preference regards the power assumptions as well.

Within combat range - stealth is best achieved by taking out opponent's sensors...

 

[HG_B]

Detection outside combat range is not a given just because a ship is radiating. Such depends on resolving power and factors of resolution and integration times

Using current household tech (in space of course), a heat source as small as the shuttles maneuvering thruster can be easily detected as far out as the asteroid belt. A personal camera that views into the IR band could sweep the entire spherical solar system in ~4 hours.

So yes, detection IS a given...

 

[BytePro]

There is a lot more to usefully detecting something than just the sensitivity of a detector.

As to 'sweeping the entire spherical solar system in ~4 hours' with a hand held camera - you won't get anything useful with such. WISE spent 6 months doing a full sky survey - with a 6 arcsecond resolution, IIRC. Out were the Voyager probes are it couldn't detect something the size of our Moon radiating in human black body temps...

So - not a given outside combat ranges. How far and to what extent is entirely a IYTU thing in CT.

 

[HG_B]

There is a lot more to usefully detecting something than just the sensitivity of a detector.

As to 'sweeping the entire spherical solar system in ~4 hours' with a hand held camera - you won't get anything useful with such.

Incorrect. I'm talking about the IR temps I listed. Restudy.

 

[BytePro]

No need. But feel free to share your findings with NASA.

 

[HG_B]

No need. But feel free to share your findings with NASA.

Already have. They have been using them for decades now.

(I'll give you a hint to start your physics problem) Where are you dumping the heat from your ship's fusion PP?

 

[Matt123]

Interesting physics debates aside, the solution for most systems concerned about this is to scatter cheap passive IR sensor platforms at far orbit.

A mere 6 will enable detection of most attempts to use IR shielding within the system, with more (or the assumption of more) making the shielding job progressively more difficult & expensive.

Of course I'm assuming at typical TL's (12 or so) sufficient IR range, sensitivity and cheap all come in the same package.

I think given the ease any system can detect such attempts, the problem for intruders comes back to looking at heat sinks for solutions.

Maybe the answer is at much higher techs when it might become possible to launch waste heat into jump space from within the shielded vessel.

 

[sabredog]

I have usually had the good fortune to play with people who tended to suspend disbelief while playing Traveller and have simply accepted things work a certain way in a universe with reactionless drives, small fusion plants, and anti-grav assisted handheld fusion guns.

So if I tell them the scoutship they are looking at has the latest stealth technology to make it nearly undetectable at normal ranges by current means they just nod and say 'OK'. Then, rather than argue for hours over how much heat is detectable over distances we already find hard to imagine while flying in ships none of us will ever see (expect in the hands of our alien overlords) in our lifetimes, we instead just get on with having a good time playing the game.

It isn't that good, hard science doesn't have a place in the world, it just isn't at my gaming table unless the game I'm playing is about good hard science and properly supports it in all areas. Just like scifi literature: sometimes you want some Clarke (you know, for proper nutrition and fiber), and sometimes you just feel like gorging on Vance (plenty of juicy pulp chased with a Twinkie). It's a mindset thing depending on the genre: in CoC the Elder Gods are coming when the stars are right and nobody says "That's silly", and in Traveller we all jump into our ship and with the push of a button zoom off to another star in a week an no one says, "That's silly, and what about time and distance relative to our motion, blah, blah, blah..." If someone did we'd take away his Cheetos.

Just tell the players it works IYTU and if they ask how tell them it's because it does, maybe with reasonable (or reasonable-sounding) details. If they argue then destroy their ship with it while they argue how impossible the thing you came up with should be. Tell them you find their lack of ability to suspend disbelief disturbing.

 

[sabredog]

BTW: as for the detection rules as they exist...meson neutrino sensors are one of the guidance systems available for missiles in the expanded missile supplement and they supposedly home in on the powerplant. Meson communications that are not hindered by intervening planets (in space) and mountains (on the ground) are standard by TL15 if not earlier.

Those things would tend to imply that there are plenty of pretty precise ways of finding and tracking objects in space that use fusion reactors other than just heat reflection or emission. So since you can't mask the neutrino source well enough to spoof a missile's seeker, or stop a meson radio in a jeep, maybe it isn't worth the effort to mask a ship at all? At least not until you can build (or find) a black globe, which the rules point out is the only way to prevent detection.

 

[Carlobrand]

I learn so much here!

However, let's focus a bit. I'm not here to start another debate about stealth. That's a fun debate but we've got two or three - or more - tech levels of advance between here and there that, within certain physical limits, can tip the debate in either direction, at least with respect to some pirate sneaking up on some hapless free trader in a poorly patrolled system. I can't see a fleet or a civilized system being vulnerable to that kind of thing - all scientific debates aside, people in large groups are pretty clever about solving the problems they face with whatever tools are at hand.

Question at hand is more one of targeting.

IYTU anything is possible and the only people that have to answer that are the players and the GM.

And the GM needs help developing a variant that would make sense to players.

 

[Enoki]

Basically, with a starship any homing system would see it as a point source at the kind of distances we are looking at in space combat. That is, a missile, etc., won't differentiate between one part of the ship and another until it gets very close. Any sort of defense system trying to confuse or jam tracking systems would likely have to be off-platform like flares, and other active or passive sources that look like the target.
The only other source would be background 'noise' from natural sources. These would normally be filtered out so they are likely irrelevant.

 

[HG_B]

Question at hand is more one of targeting.

Targeting should be no problem using IR. We already use IR for missile homing. The limitation is that Earth's atmosphere absorbs IR so range is short. In space that isn't a factor. Also, once close enough the missile can use a laser to paint the target for a harder lock.

 

[Carlobrand]

BTW: as for the detection rules as they exist...meson neutrino sensors are one of the guidance systems available for missiles in the expanded missile supplement and they supposedly home in on the powerplant. Meson communications that are not hindered by intervening planets (in space) and mountains (on the ground) are standard by TL15 if not earlier.

Those things would tend to imply that there are plenty of pretty precise ways of finding and tracking objects in space that use fusion reactors other than just heat reflection or emission. So since you can't mask the neutrino source well enough to spoof a missile's seeker, or stop a meson radio in a jeep, maybe it isn't worth the effort to mask a ship at all? At least not until you can build (or find) a black globe, which the rules point out is the only way to prevent detection.

"Meson" neutrino sensors? Mesons and neutrinos are different beasties, no? There are muon neutrinos, electron neutrinos, and tau neutrinos, and fusion reactions emit electron neutrinos (although there's some deal about the neutrinos oscillating between different flavors). There are anti-neutrinos of all three flavors, and fission reactions emit electron antineutrinos, but supposedly it's not yet clear whether they're different from their alternate versions. There are pi mesons, which decay into muon neutrinos and anti-muons, or electrons and electron antineutrinos. There's supposed to be a process for making a neutrino beam using a particle accelerator and pi mesons. There is continuing debate over some of these points, because a lot of this is very recent findings. And if you ask me what any of that means in English, I will deny knowing you. :devil:

Neutrino detectors are elaborated on in MegTrav. The ones small enough to fit in a missile are described as, "Nondiscriminant direction sensor only. Simply indicates the direction to the highest neutrino source, depending on the range
setting." Since the highest source would always be your ship, one presumes there's some method for telling it to ignore this or that source, else it's not useful for anything. I guess the firing ship gives them a lock on the target to be hit, and they use the detector to keep themselves pointed at the selected target until they hit it. Thing is, if the detector can't read magnitude, then a stronger neutrino source passing between them and the target, or diverging from the target, may cause the missile to instead follow that source.

If the neutrino detector is unable to discriminate, then a fission reaction might be used to "flash" a brief blast of neutrinos (well, antineutrinos) to distract the detector. Consider a countermeasure based on a few grams of nuclear material rapidly condensed in a conventional explosion: too little to actually create a nuclear explosion, it would nonetheless undergo very rapid fission, emitting a sudden burst of neutrinos. Such an event at a critical moment might distract the missile, causing it to briefly veer toward the flash so that, by the time it reacquired its target, its momentum will have carried it past the opportunity for intercept. Of course, that is predicated on whether the hypothetical future-tech missile-size detector can or can not tell a neutrino from an antineutrino. This is all sufficiently beyond my knowledge base that my best answer is, "How the heck should I know."

Of course, to a shipboard sensor, it'd just look like something went flash a little to one side of the main neutrino source you're tracking. Shipboard neutrino sensors are a good deal more robust.

If it is possible to build a neutrino beam of reasonable size, then that might also serve as an electronic countermeasure - blinding the missile with neutrinos.

Another, though expensive, option is to launch a countermeasure built around a very small fusion reactor directly at the inbound missiles and let proximity do your work for you. MegaTrav offers a TL14 microplant for about Cr20,000, cheap considering the price of the ship it's intended to protect. As it approached the missile, the countermeasure's output would appear equal to and then brighter than the original target and, coming directly at them from the bearing of the original target, it is likely that the missile would read the image as its target suddenly coming closer to it, therefore choosing to impact the countermeasure.

That one's not in the game, at least not visibly so - in the High Guard world of infinite missiles, it might be an unmentioned defense that accounts for the missiles' missing in the first place. It would be a neat addition. Considering that a missile runs Cr20,000 itself, and that a single Cr20,000 countermeasure could possibly distract an entire battery (since they're all launched at the same time and on the same bearing), it's a cost-effective defense.

FYI: meson communications appear at tech level 15 and are very expensive. Depending on which rules set you use, they range from Cr250,000 for a 500km range model (MegaTrav) to Cr1,000,000 for a 100km range model (Striker), and get worse from there - compared with Cr 22,000 for a comparable maser communicator. They are not standard. They are special-use alternatives applied when the more traditional laser/maser communicators won't do the job, as for example communicating with a deeply buried bunker or when circumstances won't let you plant a maser repeater atop the mountain or bounce a signal off a satellite. Warships would carry one, but civilian ships don't have much need for communicating through the body of a planet to a receiver on the other side of a planet; simpler to rely on the local satellite grid or plant your own satellites - MegaTrav has them at Cr 35,000, equip them with maser comms and you've got yourself a communications satellite.

 

[sabredog]

Targeting should be no problem using IR. We already use IR for missile homing. The limitation is that Earth's atmosphere absorbs IR so range is short. In space that isn't a factor. Also, once close enough the missile can use a laser to paint the target for a harder lock.

Once the missile switches to laser guidance it will be easier to spoof, as happens today unless there is someone nearby painting the target manually to ensure the missile hits the right target. Even then some systems like Shtora do a pretty good job of spoofing operated guided systems with dazzlers that may overcome the onboard guidance systems.

Neutrino guidance systems as described in the rules supplement would be a lot harder to fool unless decoy drones were used since the emissions by a larger warship would be tremendous and impossible to mask. Timing would be, as in all things, critical in using the decoys but along with batteries of anti-missile lasers and sand (which would further mess up laser guidance systems used by a missile) would help strip away incoming missiles.

 

[HG_B]

Once the missile switches to laser guidance it will be easier to spoof,

It wouldn't switching but, augmenting.

 

[sabredog]

It wouldn't switching but, augmenting.

Ok, but they still wouldn't be very useful. On the IR side the missile would have, in a battle, a lot of background clutter from explosions, lasers from myriad batteries, other missile exhausts and heat sources, and all of the other ships around burning bright with their own IR signature.

The laser side of it would be even more confused trying to sort out the correct signature among all of the other lasers around and sand. Which is probably why that kind of guidance system isn't included as an option in the canon supplement. On the other hand, mass (TL 10) and neutrino (TL 11) sensors are.

One type mentioned but not codified could be a target memory guidance package similar to what is described in Striker: if it has the image of the specific ship locked into its guidance system with a fresh electronic emissions signature provided by the launching ship's sensors and fire control systems before firing it would be pretty hard little bugger to fool.

 

[HG_B]

Ok, but they still wouldn't be very useful. On the IR side the missile would have, in a battle, a lot of background clutter from explosions, lasers from myriad batteries, other missile exhausts and heat sources, and all of the other ships around burning bright with their own IR signature.

Nope. Space is MUCH bigger than you envision...

 

[warwizard]

ECM can be used to spoof any active sensor by sending fake return pulses at higher power levels than the true returns. The timing of these false returns is used to make the sensor see the target accelerating towards or away from the target as desired causing the weapon system to make errors in range.

The other answer to the heat generation problem is you do not generate the heat in the first place, have your laser capacitor banks already fully charged, insides of the ship pumped down to vaccuum and all the crew in their space suits with 6 hours of endurance. The ship's radiators were used prior to battle/ making the approach to bring the ship's hull to asteroid normal temperatures. The life support is turned off the G-comp is off, the freshers in the staterooms are off, every thing not essential is turned off. Any device that uses power generates heat as it converts that power into work or transforms it into another form of energy, the power plant providing that power ALSO generates the same heat inside it's generator a 250 MW power plant at full output generates 500 MW of heat load, 250 MW inside the generator and 250 MW in the wiring and devices utilizing that power (minus whatever was actually converted to another form of energy ... 20% efficient Grav foccussed lasers as an example). If no devices are using power the generator is also not generating heat. The fusion reactor can brought to a power level = to that TL's minimum size plant's output. For TL= 15 that's 600KW, TL 11 , not much help there it's 800 MW for them (T4 FF&E assumption from minimum PP size entry).

Nutrino sensors expect that the power plants stay operating, shut down the ship's power plant while launching a high g missile (fusion power and Heplar) at some vector calculated to get close fast and allow your PP to be brought back up slowly but allways at a intensity calculated to have an relative magnitude less than that of your decoy's relative magnitude.